1. Field of the Invention
The present invention relates to a process for carrying out a multiphase reaction in which at least three reactants are involved, a process for preparing carboxylic acids by hydrocarboxylating olefins, products obtained by the multiphase reaction process, and uses thereof.
2. Description of the Related Art
Tertiary carboxylic acids may be used for the preparation of siccatives, peroxides and lubricants. A further field of use of tertiary carboxylic acids is the preparation of unsaturated esters such as vinyl esters, from which co-oligomers or copolymers are prepared.
Since the 1960s, the direct carbonylation of olefins with carbon monoxide to give carboxylic acids using strong acids as a catalyst (Koch reactions, in New Synthesis with Carbon Monoxide, J. Falbe (Ed.), Springer, Berlin, 1980, p. 372) has been known. Later, it was found that the reaction can additionally be catalyzed by silver or copper cations (Y. Souma, H. Sano, Bull. Chem. Soc. Jpn. 1974, 47, 1717). These reactions, irrespective of the starting olefin, form predominantly tertiary carboxylic acids when the starting olefin has a sufficiently large number of carbon atoms (e.g., n in the formula specified below is greater than 3):CnH2n+CO+H2O→R1R2R3C—COOH where (R1+R2+R3)=Cn−1H2n+1 catalyst
Industrially, these reactions are typically carried out in stirred reactors at from 40 to 70° C. and from 70 to 100 bar of CO pressure using a BF3/H2O or BF3/H3PO4/H2O catalyst. The use of catalysts having Cu ions allows the reaction to be carried out even at ambient temperature and standard pressure.
Disadvantages in all known processes include the oligomerization of a portion of the olefins to form oligomers which may partly convert to higher carboxylic acids. A further disadvantage is a low mass transfer between the phases thus resulting in low space-time yields.